The most vulnerable leg of the Pentagon’s nuclear triad showed deepening rot on Wednesday, as the Air Force announced that 34 of its missile-launch officers may have been implicated in cheating on a proficiency test and have been removed from their place in the nuclear-launch chain of command.

Service officials said they believe it marks the biggest wholesale ouster of nuclear-certified officers in Air Force history, officers charged with commanding and controlling the world’s deadliest weapons.

The Air Force’s land-based missile leg is the shakiest among the three means of delivering atomic warheads because, as budget pressures mount, experts say it is the leg most likely to be scrapped.

Military officers say the Navy’s missile-launching submarines are the most secure, and Air Force bombers are more secure than the service’s missile fleet because the aircraft can also perform nonnuclear missions (the B-1 bomber, originally designed to wage an atomic war with the Soviet Union, lost its nuclear mission nearly 20 years ago and lately has been used as a close-air support aircraft coming to the aid of troops on the ground).

But the airmen overseeing the LGM-30 Minuteman III force 24/7 from their bunkers buried up to 100 ft. (30 m) deep in mid-America have no mission other than their nuclear assignment. Despite the protests of the commanders that their jobs remain vital, there’s a palpable sense among Pentagon officials that the nuclear moment — and the honor and glory that once came with it — has faded in recent decades. Nowhere is that felt more deeply than in the Air Force’s intercontinental-ballistic-missile force.

In the past year, there have been reports of poor morale among the so-called missileers presiding over the nation’s 450 missiles divided among Malmstrom Air Force Base, Mont., Minot Air Force Base, N.D., and F.E. Warren Air Force Base, Wyo. Last month, the Air Force inspector general released a report about the boorish behavior of their two-star commander while on an official trip to Moscow last summer, leading the service to remove him from his nuclear-command role.

The Air Force uncovered the cheating while investigating a scandal that broke last week involving three missile officers suspected of illicit drug use. That probe has grown to include eight other nonnuclear Air Force officers, spread across six bases. It also led to the cheating allegations involving 34 young officers — 2nd lieutenants and captains — overseeing 150 Minuteman III missiles, one-third of the land-based ICBM force, at Malmstrom.

“This was a failure of integrity on the part of some of our airmen,” said Air Force Secretary Deborah James, who has been in charge only since Dec. 20. “It was not a failure of our nuclear mission.”

The service’s top uniformed officer agreed. “The operational capability to conduct the mission is not impacted at this point in time,” General Mark Welsh said.

According to the Air Force officials, a missile-launch officer with the 341st Missile Wing at Malmstrom texted answers to a monthly missile-launch officer proficiency test with 16 fellow officers in the August-September time frame. Seventeen additional missile-launch officers at the base knew of the cheating but didn’t report it up the chain of command as required. The 34 represent about 18% of the 190 missile-launch officers in the wing.

Over the coming decade, it will cost $24 billion to operate and modernize the ICBM force, the Congressional Budget Office estimated last month.